Alcohol use disorders (AUDS) impact millions of individuals and constitute one of the most serious public health problems worldwide. Despite its devastating impact on society, only a few effective medications are currently available. Orexins/hypocretins are hypothalamic peptides that act via orexin receptors that have been linked to regulating feeding and sleep. In addition, the orexin system has been shown to play an important role in alcohol self-administration and in stress-induced reinstatement. These effects are thought to be mediated by orexin containing neurons that project from the lateral hypothalamus to the ventral tegmental area (VTA) and nucleus accumbens (NAc) or from the perifornical regions to the amygdala respectively. However, the role of orexins through orexin receptors and their signaling pathway in driving ethanolmediated behaviors is less explored. The overall goal of this research project, component 6 of the NIAAAGallo Center application is to determine the role of orexins, orexin receptors and their downstream signaling pathways in different brain regions in ethanol-mediated behaviors. The Center provides a unique opportunity to apply a multidisciplinary approach that integrates behavioral, biochemical and electrophysiological techniques in the latest animal models of binge drinking, ethanol selfadministration and stress-induced reinstatement. The research aims to understand the role of orexinmediated synaptic and cellular mechanisms in the central amygdala, VTA and NAc using behavioral models of alcohol addiction. In Aim 6.1, we will determine whether Ox-Rs in the central amygdala drive stress-induced reinstatement of ethanol seeking. In Aim 6.2, we will apply electrophysiological and biochemical techniques to dissect the signaling pathways underlying orexins effects in the central amygdala. In Aim 6.3, we will determine the mechanism of action of orexins in the VTA and the NAc in regulating binge ethanol consumption and ethanol self-administration. Orexins/hypocretins play a crucial role in addiction, the sleep-wake cycle, motivation and stress, and this provides a strong rationale for our proposed studies, the experiments outlined have been designed specifically to lead to clinical studies aimed at determining the efficacy of orexin receptor antagonists in human subjects with AUDs.